The contribution of hydropower in meeting electric energy needs: The case of Turkey

Renewable Energy 51 (2013) 206e219

Contents lists available at SciVerse ScienceDirect

Renewable Energy journal homepage: www.elsevier.com/locate/renene

The contribution of hydropower in meeting electric energy needs: The case of Turkey Adem Akpınar* Gümüs¸hane University, Civil Engineering Department, 29000 Gümüs¸hane, Turkey

a r t i c l e i n f o

a b s t r a c t

Article history: Received 2 June 2012 Accepted 7 September 2012 Available online 24 October 2012

In this article, an attempt is made to better understand the contribution of hydropower in meeting electric energy needs of Turkey. Thus, a comparison between Turkey and other countries, which have some similarities with Turkey or which are more developed nations compared to Turkey, for evaluating from different aspects the contribution of hydropower in meeting electric energy needs is performed. The producers of electricity and hydroelectricity in the world, and the electric sectors of all the selected countries are firstly examined. Thereafter, Turkey’s water resources and its potential, hydropower potential, and current status of hydropower in Turkey are investigated in detail. A detailed discussion regarding economic and energy indicators, hydroelectricity versus thermal electricity, the contributions of hydroelectricity to the total and renewable electricity generation, and the usage status of hydro potential of each selected nation is also made. Finally, it is found that hydropower is the second largest contributor in meeting Turkey’s electric energy needs after thermal, mainly natural gas. It is also estimated that the contribution of hydropower will continue because a vast amount of its economically feasible hydro potential (about 64%) is undeveloped. Besides, it is determined that the contribution of hydropower in the total electricity generation in Turkey is greater than that of China and India, but it is lower than that of Norway, Brazil, and Canada. Ó 2012 Elsevier Ltd. All rights reserved.

Keywords: Hydropower Hydro potential Electricity generation Turkey

1. Introduction Energy is required in each field of commercial and human activities. Energy generation is one of the major key factors for economic and social development in all the developed and developing nations of the world. Fossils fuels like coal, petroleum, and natural gas are conventional sources of energy available in almost all countries, but their fast depletion, high prices and pollution problems forces to explore other clean and sustainable sources for energy generation. The use of renewable sources is the most valuable solutions to reduce the environmental problems associated with fossil fuels based energy generation and achieve clean and sustainable energy development. Hydro, wind, biomass, solar and geothermal is important renewable sources for energy generation. All the nations of the world are shifting their focus to extract energy from the renewable sources. Among all renewable sources, hydropower is a clean and common source, providing about 88% of the world’s electric power [1]. It has remained by far the most

* Tel.: þ90 456 233 7425x1146; fax: þ90 456 233 7427. E-mail addresses: [email protected], [email protected]. 0960-1481/$ e see front matter Ó 2012 Elsevier Ltd. All rights reserved. http://dx.doi.org/10.1016/j.renene.2012.09.049

important of the renewables for electrical power production both in Turkey and the world [2]. There are many studies related to hydroelectric potential and its usage [3], electricity generation from multipurpose dams [4], environmental evaluation of hydropower systems [5], small hydropower [6], regional assessment of hydropower [7], hydraulic modelling and its future estimation [8], hydropower policy [9] for Turkey in the literature. These and similar studies address hydropower in Turkey from different perspectives, but they do not compare Turkey with other countries, which have some similarities with Turkey or which are more developed nations compared to Turkey. This study aims to fill the gap by providing a detailed comparison and assessment of hydropower in Turkey and in some developed and developing countries. Canada and Norway were selected as developed countries because they have such an important hydro contribution in their total electricity generation while Brazil, China, and India were chosen as developing nations because they are important hydro producers and have some similarities with Turkey. Geographical locations of these countries are seen in Fig. 1. This paper firstly presents producers of electricity and hydroelectricity in the world, and then, the electric sectors of all the selected countries. Electricity generation by fuel of all the selected

A. Akpınar / Renewable Energy 51 (2013) 206e219

207

Fig. 1. Geographical locations of the selected countries (with red color) in the study. (For interpretation of the references to colour in this figure legend, the reader is referred to the web version of this article).

nations was compared with each other. Thereafter, the importance of hydropower energy as an energy source in Turkey is discussed. In this context, Turkey’s water resources and its potential, hydropower potential, and current status of hydropower in Turkey are investigated in detail. In addition, there is a discussion of the contribution of hydropower to electricity generation in all the selected countries, determining the differences between Turkey and other countries. Within this framework, economic and energy indicators, hydroelectricity versus thermal electricity, the contributions of hydroelectricity to the total and renewable electricity generation, and the status of usage of hydro potential of each selected nation are examined and compared to each other. 2. Producers of electricity and hydroelectricity in the world Electricity production amounts for the leading countries are given in Table 1. The first two leading countries are US with 4165 TWh and China with 3696 TWh. These countries have 39.2% of the total production in the world. The largest hydropower producer in 2009 was the People’s Republic of China (616 TWh/yr), followed by Brazil (391 TWh/yr), Canada (364 TWh/yr), the United States (298 TWh/yr), Russian Federation (176 TWh/yr), Norway (127 TWh/yr), and India (107 TWh/yr). The first four leading countries meet almost half of Table 1 Producers, net exporters, and net importers of electricity in the world [10]. Producers United States China Japan Russia India Canada Germany France Brazil Korea Rest of the world World

TWh

% of world total

Net exporters

TWh

Net importers

TWh

4165

20.8

Paraguay

45

Italy

45

3696 1041 990 899

18.4 5.2 4.9 4.5

34 26 15 14

Brazil United States Finland India

40 34 12 10

603

3.0

Canada France Russia Czech Republic Germany

12

586 537 466 452 6620

2.9 2.7 2.3 2.3 33.0

China Norway Spain Ukraine Others

11 9 8 6 50

Hong Kong (China) Argentina Croatia Iraq Hungary Others

20055

100.0

Total

230

Total

8 6 6 6 6 68 241

the total hydro production in the world. Turkey takes the 16th place amongst the world countries with 35.96 TWh/yr of its hydropower electricity. Table 2 shows main producers of hydroelectricity in the world. As can be seen from this figure, China, Brazil, Canada, Norway, and India are the important hydropower producers. Therefore, this characteristic of these countries has become a reason to select them as case study countries in this study. When the proportions of hydro in total domestic electricity generation are considered, it is also seen that Norway is the leading country. This country produces 95.7% of its electricity in hydro plants, followed by Brazil, Venezuela, Canada, and Sweden with 83.8%, 72.8%, 60.3%, and 48.3, respectively. While China being a country focused in this study has 16.7% of the internal electric energy production from hydroelectric power, it is 11.9% for India. The first top ten producers in hydro proportion of total domestic electricity generation are also shown in Table 2. 3. The electric sectors of the selected countries Total electricity supply in Turkey reached 194.8 TWh in 2009, up by 51% from 2000. Natural gas fuelled 49% of power generation, while coal provided 29%, hydropower 18%, oil 3% and other sources 1% (Fig. 2 in which the data was obtained from [11]). Following the contraction of the Turkish economy in 2009, electricity supply fell 2% from 2008, but according to the transmission system operator, has returned to growth in 2010. Turkey is a net exporter of electricity, but on a small scale. In recent years, annual exports have averaged around 2 TWh and annual imports less than 1 TWh. Electricity generation has more than tripled from 58 TWh in 1990, but the generation mix has remained fairly stable. Coal, gas, oil and hydropower provided all electricity in 1990 and 99% of the total in 2009. Within that group, combined-cycle gas turbines have been penetrating rapidly; coal-fired generation has also increased markedly, while hydropower and oil have seen their shares decline. From 2000 to 2009, gas-fired generation grew by 48 TWh, accounting for 72% of total incremental power generation. Coalfired grew by 17 TWh, accounting for a quarter of the incremental demand. Hydropower generation varies according to annual hydrological conditions, and increased by 5 TWh from 2000. Oil-fired generation peaked in 2002 and is steadily declining. Power generation in Turkey is set to grow strongly over the long term. Government projections that were made before the economic downturn expect total generation to increase by some 300 TWh

208

A. Akpınar / Renewable Energy 51 (2013) 206e219

Table 2 The contribution in total domestic electricity generation, producers, and installed capacity of hydroelectricity in the world [10]. Producers

TWh

% of world total

Installed capacity

GW

Country (top-ten producers)

% of hydro in total domestic electricity generation

China Brazil Canada United States Russia Norway India Venezuela Japan Sweden Rest of the world World

616 391 364 298 176 127 107 90 82 66 1012 3329

18.5 11.7 10.9 9.0 5.3 3.8 3.2 2.7 2.5 2.0 30.4 100.0

China United States Brazil Canada Japan Russia India Norway France Italy Rest of the world World

168 100 78 75 47 47 37 30 25 21 324 952

Norway Brazil Venezuela Canada Sweden Russia China India Japan United States Rest of the world World

95.7 83.8 72.8 60.3 48.3 17.8 16.7 11.9 7.8 7.1 13.9 16.5

from 2008 to 2020. These scenarios will be updated in the near future on the basis of the new targets included in the May 2009 Electricity Market and Security of Supply Strategy. The strategy foresees rapid economic growth and large increases in supply from the currently dominant sources, especially hydropower and lignite, but also from wind and nuclear power, a new entrant-to-be to the power mix [12]. Brazilian electricity production is considered to be one of the cleanest of the world, due to the high percentage of hydro energy capacities of the country (Fig. 2). The high contingent of hydro energy in the electricity matrix results in a very positive ecological balance on the one hand, but on the other, it comes with a high dependency on sufficient rainfall. The last greater energy shortage that occurred in 2001 due to a lack of rainfall has drawn attention to this problem and Brazil has been trying to build new capacities since then e increasing the share of natural gas that is used for electricity generation, but also by increasing new hydro plants since

CHINA

Oil 0%

Natural gas 1% Biofuels and waste 0% Nuclear 2%

Hydro 17%

Coal 79%

Geothermal 0%

the country’s potential in this segment is not being fully exploited [13]. Brazil, South America’s largest country and leading energy consumer, faces the twofold challenge of energy and environmental security. More than 80% of Brazil’s installed generating capacity of about 70000 MW is hydroelectric, generated by the nation’s 450 dams, which explains why Brazilian power generation is cleaner with regard to local pollutants and greenhouse gas emissions [14]. The rest of Brazil’s electricity generation mix comes from natural gas 3%, oil 3%, coal 2%, nuclear power 3%, and new renewables such as biomass, small hydro and wind power 5% (Fig. 2). Canada is the world’s second-largest producer of hydroelectricity, which accounted for 58% of Canada’s electricity production in 2007. Canada produced 639.8 TWh of electricity in 2008, 57.7 TWh of which was exported to the nearby United States. Other sources of electricity include nuclear, coal, natural gas and small volumes of non-hydro renewable energy sources. Production, trade

Oil 3%

INDIA

Biofuels and waste 0% Nuclear 2% Coal 69%

Biofuels and waste Nuclear 5% 3% Total production: 466.5 TWh/yr

Total production: 899.4 TWh/yr

Geothermal 0% wind 1%

Coal 0%

Nuclear 0%

TURKEY

Biofuels and waste 0%

Geothermal 0%

Hydro 18%

Natural gas 3% Biofuels and waste 0% Nuclear 0%

CANADA

Natural gas 49%

Coal 29%

Geothermal 0%

Wind 1%

Solar PV and thermal 0%

Oil 0%

Total production: 132.8 TWh/yr

Natural gas 3%

Solar PV and thermal 0%

1%

Hydro 96%

Hydro 84%

Geothermal Solar PV and 0% thermal 0% Wind 0% Coal 2% Oil 3%

Wind 2%

Total production: 3695.9 TWh/yr

Solar PV and thermal 0%

Geothermal 0%

Hydro 12%

Solar PV and thermal 0% Wind

NORWAY

BRAZIL

Natural gas 12%

Coal 15%

Hydro 60%

Oil 2%

Nuclear 15% Oil 3% Total production: 194.8 TWh/yr

Solar PV and thermal 0% wind 1%

Natural gas 6% Biofuels and waste 1%

Total production: 603.2 TWh/yr

Fig. 2. The ratio of energy sources in total electricity generation in 2009 for the selected countries.

A. Akpınar / Renewable Energy 51 (2013) 206e219

and energy sources vary greatly throughout the provinces and territories. The structure of the electricity sector has been changing over the past decade and, in most provinces, there has been a move from vertically integrated utilities (often provincial Crown corporations) to various degrees of market liberalization although market design and regulation differ from province to province. Production of electricity in 2008 was greater than in 2007 (617 TWh) and 2006 (592 TWh). Electricity is generated from a reasonably diversified mix of sources. The majority of supply came from hydropower, 364 TWh or 60%, while nuclear, coal and, to a lesser extent, natural gas provided the majority of remaining production. In 2009, coal contributed about 91.7 TWh (15%), nuclear power 90.4 TWh (15%), and natural gas 37.5 TWh (6%). Small volumes of electricity (3%) were produced from oil and combustible renewables and waste while other non-hydro renewables made a negligible contribution (Fig. 2). Output by energy source varied greatly from province to province [15]. Norwegian electricity generation was amounted to 132.8 TWh in 2009, a 6.9% drop from 2008. Hydropower generated 127.1 TWh (96% of the total); thermal power 4.4 TWh (3%) and wind power 1 TWh (1%). Fig. 2 shows Norwegian electricity generation by fuel in 2009. Electricity generation can vary widely from one year to another, depending on rainfall and reservoir inflow which affect hydropower availability. Since 2000, hydropower generation has ranged from a low of 106 TWh in 2005 to an all time high of 140 TWh in 2008. The record year was a relatively rainy one, with above average inflow to the hydro reservoirs, which helped push the share of hydro to 99% of total generation. Total installed generating capacity was 31257 MW at the end of 2009. Hydropower capacity amounted to 29626 MW (of which 1336 MW pumped storage), thermal capacity to 1200 MW, including two 150 MW reserve gas turbines in central Norway, and wind power capacity to 431 MW. Somewhat more than 80% of the total installed capacity is available in the winter season. Construction of gas-fired capacity is limited by an obligation to use carbon capture and storage technology in all new plants. Norway has a large reservoir capacity of 84.1 TWh (as of May 2010), and typically 60%e70% of hydropower comes from these reservoirs. Reservoir-based hydropower has a high regulating capacity and is therefore well suited to balancing variations in the increasing wind power generation both in the Nordic and Central European market areas. As of the beginning of 2010, Norwegian Water Resources and Energy Directorate, the regulator, had granted licenses to 1100 MW of new hydropower projects, around 1700 MW of thermal power projects and 1900 MW of wind power projects. Some of these license decisions have been appealed, however [16]. India’s power sector is highly dependent on coal, which has about 52% of installed power capacity. Most of the coal capacity has been added over the last three decades. Gas capacity has increased since the 1990s, as a result of several factors. Steps to liberalize the Indian economy after the crisis in 1990/91 led to an accelerated build-up of the necessary gas supply infrastructure. In addition, the start of liberalization of the power market allowed industrial consumers to become less dependent on unreliable public supply by building their own gas based plants. Due to lower impact on land and air pollution, these faced less local opposition than coal power projects. Total Indian installed capacity stood at 168 GW on 31 March 2008, of which 143 GW was utility-owned, with shares as follows: coal (53.1%); hydro (25.1%); gas (10.3%); renewable energy sources (7.8%); nuclear (2.9%) and diesel (0.8%). To ensure the supply and quality of their power requirements, many industries have installed their own plants. Of the 25 GW of industrial, captive (privately owned) plants 47.1% was coal-based, 34.6% diesel, 16.8% gas, 1.2% wind and 0.2% hydro. Almost one-third of industrial electricity demand was provided by captive power plants in 2007/

209

08; this share was much lower in the United States (17%) and OECD Europe (23%). The enactment of the Electricity Act 2003 in India eased the regulations for industrial concerns building power plants and allowed industry-owned plants to feed electricity into the public grid. As a consequence, captive power capacity grew by 57% between 2002 and 2009, compared to a growth of 41% in public capacity. Since 2003 the number of new hydro plant installations has also increased, thanks to better preparation of hydro projects by avoiding errors made in past projects (e.g. delay in equipment ordering, poor geological assessment, environmental clearance, land acquisition), leading to shorter implementation times. The installed capacity mix is different from the actual electricity generation mix, as load factors depend on the type of plant. About two-thirds of all power was generated from coal- and lignite fired plants (Fig. 2) [17]. The Chinese electricity sector has expanded rapidly in recent decades. According to national statistics, more than five times as much electricity was generated in 2007 as 1990. The Chinese electricity sector has been dominated by coal-fired generation, which accounted for around 80% of national electricity in 2009. Hydro is the most common renewable source, contributing around 17 per cent of electricity generation in 2009. There are also small amounts of nuclear and wind (Fig. 2). The share of renewables in total electricity generation was fairly stable between 2005 and 2009 at around 17 per cent [18]. The features of China’s energy structure determine such a power mix with coal power as the major component. The coal resources in China account for 11% of the world’s total coal reserves, and oil and natural gas account for 2.4% and 1.2% of the total reserves, respectively. During a relatively long period in the first three decades of the 21st Century, the primary energy mix with coal playing a dominant role will not be changed. However, such a power mix with coal playing a dominant role has brought along a series of problems. Among them, the major problems are the huge consumption of the non-renewable coal resources and the increasingly deteriorating environmental pollution [19]. As can be seen from Fig. 2, while the primary source of electricity generation both in Canada and Norway being developed nations and in Brazil, which is a developing country, is hydroelectricity, it is second biggest source of electricity generation in India and China. However, Turkey’s electricity sector does not seem to fit the model of the selected countries. 4. Importance of hydropower energy as an energy source in Turkey The term hydropower is usually restricted to the generation of shaft power from falling water. The power is then used for direct mechanical purposes or, more frequently, for generating electricity. At the present, hydropower is an important energy source for generating electricity in all over the world due to its useful characteristics such as being renewable, clean, less effective to the environment, inexpensive, and a national energy source [20]. Hydropower is a proven technology for electricity generation, contributing with almost 20% to the fulfillment of the planet electricity demand. Hydro-turbines convert water pressure into mechanical shaft power, which can be used to drive an electricity generator, or other machinery. The power available is proportional to the product of pressure head and water discharge. Hydropower continues to be the most efficient way to generate electricity. Modern hydro-turbines can convert as much as 90% of the available energy into electricity. The best fossil fuel plants are only about 50% efficient. Hydropower is also renewable because it draws its essential energy from the sun and particularly from the hydrological cycle [21]. Besides, its resources are widely spread

210

A. Akpınar / Renewable Energy 51 (2013) 206e219

Fig. 3. Water budget of Turkey [24].

around the world. Potential exists in about 150 countries and about two-thirds of the economically feasible potential remains to be developed. It plays a major role in reducing greenhouse gas emissions in terms of avoided generation by fossil fuels. Hydro is a relatively small source of atmospheric emissions compared with fossil fired generating options and has the lowest operating costs and the longest plant life, compared with other large scale generating options [22,23].

4.1. Turkey’s water resources and its potential Contrary to the general thought, Turkey is not a water-rich country as it is often presumed. To the contrary, the country is vulnerable to facing water shortage problems in near future unless necessary interventions are made. This problematic status of the country in regard to water derives from several factors including the following: Difficulty of controlling resources as a result of a problematic topography; unbalanced regional

distribution of resources and precipitation; and utilization of water resources through regional, discrete and short-term projects instead of long-term planning for integrated water management on catchment basis. Per capita water usable is 1600 m3. Looking at some other countries and the world average, it is seen that Turkey is among those facing water shortage in term of per capita usable water endowment. Today, it is accepted that a country should have annual per capita water potential of more than 5000 m3 to be classified as water rich. Population of Turkey is expected to be 100 million in 2023. Then it is possible to conclude that per capita water potential in Turkey will further fall to 1125 m3 by that year. It is possible to figure out further pressures on water resources deriving from population growth and changes in water consumption patterns. It should also be noted that all these estimates are based on the assumption that existing water resources and potential are transferred to coming generations as they are now. This indicates that Turkey has to utilize its water resources efficiently and rationally to safeguard future generations [24]. Annual mean precipitation in Turkey is 643 mm, which corresponds to 501 billion m3 of annual water volume in the country. A volume of 274 billion m3 water evaporates from water bodies and soils to atmosphere. 69 billion m3 of volume of water leaks into groundwater, whereas 28 billion m3 is retrieved by springs from groundwater contributing to surface water. Also, there are 7 billion m3 volume of water coming from neighboring countries. Thus, total annual surface runoff amounts to a volume of 193 billion m3 of water. Including 41 (69  28) billion m3 net discharging into groundwater (covering safe yield extraction, unregistered extraction, emptying into the seas, and transboundary), the gross (surface and groundwater) renewable water potential of Turkey is estimated as 234 (193 þ 41) billion m3. However, under current technical and economic constraints, annual exploitable potential has been calculated as 112 billion m3 of net water volume, as 95 billion m3 from surface water resources, as 3 billion m3 from neighboring countries and as 14 billion m3 from groundwater safe yield [24]. Fig. 3 shows the water budget of Turkey. Turkey is geographically divided into 25 hydraulic basins. These basins differ widely in terms of their respective water potential and the Euphrates-Tigris basin alone makes up about 28% of the total water potential of all basins [24]. The rivers often

Fig. 4. Water potential of Turkey by drainage basins.

A. Akpınar / Renewable Energy 51 (2013) 206e219

boundaries between Turkey and the neighboring countries are along international rivers [26].

Table 3 Hydropower potential of Turkey [24]. Status of economically viable potential

In operation Under construction In program Total potential

211

Number of hydro-electric plants

Total installed capacity (MW)

Average annual generation (GWh/yr)

Ratio (%)

172 148 1418 1738

13700 8600 22700 45000

48000 20000 72000 140000

35 14 51 100

4.2. Turkey’s hydropower potential

have irregular regimes and natural flows cannot generally be considered as usable resources. Geographically, there is a large variation in average annual precipitation, evaporation, and surface run-off parameters in the country. The drainage density is relatively higher in the Black Sea region, while the density is much lower in the regions of Central Anatolia and Southeastern Anatolia [25]. Fig. 4 gives the water potential by drainage basins. The data in the figure was obtained from [24]. Total precipitation area and mean annual run-off of Turkey are 779452 km2 and 186.86 km3, respectively. The most important rivers are the Fırat River (Euphrates) and Dicle River (Tigris), both of which are Transboundary Rivers originating in Turkey and discharging into the Persian (Arabian) Gulf. The Meriç, Çoruh, Aras, Arapçay, and Asi Rivers are the other transboundary rivers. Some 22% of the

Table 4 Distribution of existing hydropower plants according to their installed capacity by 2011. Classification

Number of plant

Total installed capacity (MW)

Average annual energy (GWh/yr)

Contribution to total annual energy (%)

Large hydro Medium hydro Small hydro Mini hydro Micro hydro Pico hydro Total

46 51 96 71 25 e 193

13047.14 1207.97 298.51 291.09 7.42 e 14553.62

46165.0 4450.3 1222.9 1194.6 28.3 e 51837.5

89.06 8.59 2.36 2.30 0.06 e 100

In the determination of hydroelectric energy potential gross potential, technical and economical potential are the important conceptions. Briefly, the gross potential shows the hydroelectric energy production upper limit of a river basin, a potential that is made up by the existing height and average flow rate. Gross hydroelectric energy potential of Turkey, which is a function of topography and hydrology, is about 433.0 TWh/yr that is equal to 1.1% of the total hydropower potential of the world and 13.8% of European hydropower potential [27,28]. Technical potential shows the upper limit of the hydroelectric energy production of a river basin. Excluding the inevitable losses, this represents the hydroelectric energy production limit that is technically feasible. Technical hydroelectric energy potential in Turkey is estimated as 216.0 TWh/yr. Economical hydroelectric potential is the total hydroelectric energy from a river basin that can be technically developed and is economically coherent. In other words, the economical hydroelectric energy potential shows the hydraulic resources with economic feasibility [23,29]. As the 2009-year, economical potential of Turkey is almost 32% of the theoretical potential (nearly 140.0 TWh/yr). Although Turkey is not affluent in terms of hydroelectric energy potential, it is ranked in the first quartile within European countries. In terms of developing water resources in Turkey, hydraulic energy generation takes a considerable portion. As the beginning of 2009, there were 172 hydro plants in operation. These have a total installed capacity of 13700 MW and an annual average generation capacity of 48000 GWh, amounting to almost 34% of the total exploitable potential, which at present is meeting about 25% of the electricity demand. Under construction there are 148 hydro plants with an installed capacity of 8600 MW and an annual generation capacity of 20000 GWh, which is almost 14% of the total potential. In the future, 1418 hydropower plants will be constructed to exploit the remaining potential of 72000 GWh/yr, bringing the total number of hydropower plants to 1738 with a total installed capacity of 45000 MW (Table 3).

Fig. 5. Comparison of numbers of existing hydropower plants at different basins according to their size.

212

A. Akpınar / Renewable Energy 51 (2013) 206e219

Fig. 6. Comparison of installed capacity and energy generation of existing hydropower plants at different basins according to total and large hydro capacity.

4.3. Current status of hydropower energy in Turkey So far in Turkey, 1738 hydro plants are at various stages of development. In 2009, 172 plants have been put into operation, 148 are under construction and a further 1418 are at various planning stages. By 2011, the installed capacity and annual average energy production capability of hydropower plants in operation had reached about 14553 MW and 51.8 TWh, respectively. Thus, only 37% of the technically and economically utilizable hydroelectric potential has been developed. The classification of hydropower plants in regard to their installed power generation capacity has generally been referred to a large, medium, and small (mini, micro, and pico) hydropower plant. Large hydro is commonly classified as having a generating capacity of more than 50 MW. Systems that have an installation capacity of between 50 MW and 10 MW are referred to as mediumhydro [30]. Hydropower has also various degrees of size for small

hydropower. To date there is still no internationally agreed definition of small hydro; the upper limit varies between 2.5 and 25 MW. A maximum of 10 MW is the most widely accepted value worldwide, although the definition in China stands officially at 30 MW. In the jargon of the industry, mini hydro typically refers to schemes below 2 MW, micro-hydro below 500 kW and pico-hydro below 10 kW. These are arbitrary divisions and many of the principles involved apply to both smaller and larger schemes [31]. Distribution of existing hydropower plants according to their installed capacity in Turkey is shown in Table 4. As this table, 2.36% of all the annual energy is generated by 96 small hydropower plants (with installed capacity <10 MW), while large and medium hydro has 89.06% and 8.59% of average annual energy with 46 and 51 hydropower plants, respectively. The river basins have large differences in terms of their respective water potential and hydropower potential due to geographic properties. Figs. 5e7 present comparisons of numbers,

Fig. 7. Comparison of installed capacity and energy generation of existing hydropower plants at different basins according to their size.

A. Akpınar / Renewable Energy 51 (2013) 206e219

213

Fig. 8. Development of numbers of existing hydropower plants commissioned at different time periods according to their size.

installed capacity, and energy generation of existing hydropower plants according to size at different basins. The data obtained from [32] for these figures was updated. As can be seen from these figures, Euphrates-Tigris basin has the largest share compared to other basins for each size category of hydro in terms of numbers, installed capacity, and energy generation of plants. There are no plants at four basins (North Aegean, Meriç-ergene, Burdur lakes, and Akarçay). In terms of total hydro capacity, basins with the most important hydro potential are Euphrates-Tigris, Kızılırmak, Ceyhan, Yes¸ilırmak, Antalya, East Black Sea, East Mediterranean, Sakarya, Çoruh, and Seyhan, respectively. Other basins have a negligible capacity. Fig. 8 shows development of numbers of existing hydropower plants commissioned at different time periods according to their degree of size. The data in the figure was obtained from [32] and updated. It is understood that development of small hydro has begun before 1929 while large and medium hydro have started to be developed after 1950. Also, it is shown that development of numbers of large hydro plants has steadily increased, but there are increases and decreases in the development of numbers of small and medium hydro plants. Developments of installed capacity and energy generation of existing hydropower plants commissioned at different time periods according to their degree of size are seen in Figs. 9 and 10 in which the data was obtained from [32] and updated. From these figures, in the last 10 year period, a rapid increase are observed for both small and medium hydro due to

investments of private sector increasing after the 4628 Electricity Market Law, issued in the Official Gazette dated 3rd March, 2001, while there are decreases in the developments of large and total hydro. 5. Discussions 5.1. Economic and energy indicators Economic growth is the most important driver of energy demand. Total final consumption of electricity has been shown in many countries to be correlated with economic activity. The other reasons for increase of electricity demand are high birth rates, higher living standards, industrialization and young populations. In Turkey, like in the other developing countries, the demand for energy and electricity is growing rapidly due to the social and economic development and increase of the population of the country [33]. The relationship between electricity consumption per capita and GDP in some of developed and developing countries is shown in Fig. 11. In the figure, the developing countries are selected for comparison with Turkey since some similarities exist. Canada and Norway, which take part in developed countries, are also chosen to see the differences from the developed countries. China, Brazil, and India having rapid growth rate are the developing countries like Turkey. Fig. 11 indicates that the relationship between Turkey’s

Fig. 9. Comparison of installed capacity and energy generation of existing hydropower plants commissioned at different time periods according to total and large hydro capacity.

214

A. Akpınar / Renewable Energy 51 (2013) 206e219

Fig. 10. Development of installed capacity and energy generation of existing hydropower plants commissioned at different time periods according to their size.

electric power consumption and GDP has been erratic in the past. The electricity consumption in Turkey increased steadily during the period of 1960e2000 and after 2000 it has continued to increase but its growth rate has decreased. During this progress, a few slight decreases were observed like GDP in 1979, 1993 and 2000 was decreased. The reason is probably due to economic crises gained experience in these years. The electricity consumption per capita of

TURKEY

2500

2009

2006

2000

2001

1500

1994

1000 500

2006

2000 1500

2001

1000 1994

500

1979

0

200 400 600 GDP (Billion $)

2500 2000

2002

1500

800

BRAZIL

700

2009

600

1997

1990 1982

1000

0

500

kWh per capita

0

kWh per capita

2009

2500

0

2000 4000 GDP (Billion $)

INDIA 2009

500

2006

2002

400 300

6000

1991

200 100 0

0 0

500 1000 1500 GDP (Billion $)

0

2000

NORWAY

30000

500 1000 GDP (Billion $)

1987

25000 20000

1980

2003

2009

15000 10000 5000 0

1500

CANADA

20000 kWh per capita

kWh per capita

CHINA

3000 kWh per capita

3000 kWh per capita

Turkey increased from 95 kWh in 1960e2298 kWh in 2009 with the growth rate of 2319%. Turkey’s average electricity consumption per capita growth rate was about 7.74% between 1990 and 2000 and it was about 4.43% from 2000 to 2009 (Table 5). For the period of 1990 and 2000, the average annual electricity consumption per capita growth was 9.43%, 4.54%, and 3.00% for China, India, and Brazil. It is smaller than 1% for the developed countries. Table 5

15000

2005 2009

10000

1975

5000 0

0

200 400 GDP (Billion $)

600

0

500 1000 1500 GDP (Billion $)

2000

Fig. 11. The relationship between electric power consumption per capita and GDP for data from 1960 to 2009 in the focus countries.

A. Akpınar / Renewable Energy 51 (2013) 206e219

Norway

India

China

Canada

Brazil

6.72 20.04 7.27 4.50 22.14

4.91 10.70 8.85 23.58 35.16

11.00 21.16 11.67 2.44 9.39

17.91 45.53 9.66 3.96 16.37

4.86 9.36 4.54 5.42

9.58 8.15 9.43 18.33

5.92 4.24 2.62 0.55 1.00

13.49 4.43 3.00 1.85

Therma l installed capacity (GW)

indicates the average annual growth rates (%) of the electricity consumption per capita and GDP of the selected countries in different range. The data in the Table 5 and Fig. 11 was obtained from [34]. As can be seen from Fig. 11, both of electricity consumption and GDP of the selected developing countries except China have increased a certain extent. China’s economy and electricity consumption per capita has growing at high speed. However, in the developed countries, for first years the electricity consumption per capita has increased quickly while the GDP has

35

TURKEY

30 25 20 15 10 5 0 0

Therma l installed capacity (GW)

700

5.2. Hydroelectricity versus thermal electricity The electricity industry in Turkey dates back to 1902, when a 2 kW hydropower system was connected to a water mill in Tarsus. The whole installed capacity was 29664 kW when Turkish Republic was established in 1923 and the production was 45 GWh/year in those years and the electricity was only available in three cities, namely Istanbul, Adapazarı, and Tarsus. By 1980, installed capacity and electricity generation had increased to about 5107 MW and 23193 GWh, respectively. Installed hydroelectric power plants provided approximately 42% of the electrical power during 1980. In contrast, during the same year, 58% of the installed electrical power came from thermal power plants (Fig. 12 in which the data was obtained from [11]). In 1987, construction of Karakaya dam (1800 MW) and in 1992 construction of Ataturk dam (2400 MW) were finished and they started producing electricity. Therefore, the share of hydroelectric generation increased. Variation of electricity generation in Turkey shows a sudden and unpredictable change. From 1989 to 1998, electricity generation from hydraulic and thermal increased almost linearly. After 1998, hydroelectric generation started decreasing while thermal electricity generation increases (Fig. 13 in which the data was obtained from [11]). After

20

10 5 0

5 10 15 Hydroelectric installed capacity (GW) CHINA

600 500 400 300 200 100 0

20 40 60 80 Hydroelectric installed capacity (GW)

140 120 100 80 60 40 20 0

Therma l installed capacity (GW)

0 50 100 150 200 Hydroelectric installed capacity (GW) 0.9 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0

NORWAY

15 20 25 30 Hydroelectric installed capacity (GW)

BRAZIL

15

Therma l installed capacity (GW)

Turkey

Gross Domestic Product (GDP) 1960e1970 2.21 14.65 1970e1980 30.26 40.05 1980e1990 11.90 8.46 1990e2000 7.69 4.31 2000e2009 14.50 13.36 Electricity consumption per capita 1960e1970 14.29 7.51 1970e1980 12.59 3.90 1980e1990 8.74 2.49 1990e2000 7.74 0.70 2000e2009 4.43 0.64

INDIA

0 10 20 30 40 50 Hydroelectric installed capacity (GW) Therma l installed capacity (GW)

Range

been fixed. In the recent year, the GDP has increased rapidly while the electricity consumption grow rate has been constant.

Therma l installed capacity (GW)

Table 5 Average annual growth rates (%) of the electricity consumption per capita and GDP of the selected countries in different range.

215

40

CANADA

35 30 25 20 40 50 60 70 80 Hydroelectric installed capacity (GW)

Fig. 12. Variation of hydro and thermal electricity installed capacity from 1980 to 2010 in the focus countries.

TURKEY

3500

CHINA

3000 2500 2000 1500 1000 500 0

Thermal electric generation (TWh)

0

5

40 30 20 10 0 100

4 3 2 1 0 130 180 Hydroelectricity generation (TWh)

200 300 400 Hydroelectricity generation (TWh)

800 700 600 500 400 300 200 100 0

250 500 750 Hydroelectricity generation (TWh) NORWAY

80

50

20 40 60 Hydroelectricity generation (TWh) Thermal electric generation (TWh)

Thermal electric generation (TWh)

0

BRAZIL

60

INDIA

0

50 100 150 Hydroelectricity generation (TWh) CANADA

180 160 140 120 100 80 60 40 20 0

Thermal electric generation (TWh)

180 160 140 120 100 80 60 40 20 0

Thermal electric generation (TWh)

A. Akpınar / Renewable Energy 51 (2013) 206e219

Thermal electric generation (TWh)

216

230

280 330 380 Hydroelectricity generation (TWh)

Fig. 13. Variation of hydro and thermal electricity generation from 1980 to 2010 in the focus countries.

1987, Turkey started importing natural gas and most of it used for electricity generation. During 1986e1993, the installation of hydroelectric system increased steadily. After 1993, there is not recognizable change for the hydroelectric installation. On the other hand, thermal power plants installation showed a rapid increase after 1997 due to installation of natural gas power plants (Fig. 12). Therefore, hydroelectric generation has started decreasing while thermal electricity generation increases. Use of natural gas for electricity generation decreased the share of hydroelectricity in the total electricity generation after 1998 [7,33]. In 2010, while total electric capacity was 49524 MW, installed capacities of hydroelectric and thermal power plants reached to 15831 MW and 32278 MW, respectively. On the other hand, electricity generation of hydroelectric raised to 51278 GWh while the thermal power production increased to 146048 GWh for this year. The variations of electricity power developments of hydro and thermal installed capacity and generation for the focused countries are illustrated in Figs. 12 and 13. Annual average growth rate of thermal electric generation between 1980 and 2010 in Turkey is about 8.4% while it is 5% for hydroelectric generation. These rates for Turkey’s thermal and hydroelectricity are the second largest between the focus countries in this study. Country having the first largest rates is China with thermal and hydro generation growth rates are 8.8% and 8.5%, respectively. Annual average growth rates of thermal electricity in Brazil and India are 5.8% and 7.9% while

growth rates of hydroelectricity in these countries are 3.8% and 2.8%, respectively. As can be seen, annual growths of hydroelectricity are slower than that of thermal electricity in the developing countries. In the developed countries, annual growth rate of hydro which is about 1% is usually constant because these countries have largely developed their hydroelectric potential. 5.3. The contribution of hydropower to the total electricity generation Turkey’s main electricity production resources are hydraulic and thermal sources, mostly lignite. In the 1980s, while the total electric power was 23.3 TWh, the amount of electric energy production has steadily increased, and has grown to 201.2 TWh in 2010. Installed hydroelectric power plants provided approximately 47.9% of the electrical power of Turkey in 1980. In contrast, in the same year, 51.6% of the installed electrical power came from thermal, and renewable sources constituted the rest. The share of hydraulic electricity production declined drastically, slipping from 47.9% in 1980 to 25.5% in 2010. Simultaneously, the share of thermal electricity production raised whose share escalated from 51.6% in 1980 to 72.6% in 2010. The decrease in the share of electricity from hydraulic is due to the excess import of natural gas. This excess amount has to be used up due to insufficient storage. Therefore, some hydraulic power plants have a temporary slow down in the

A. Akpınar / Renewable Energy 51 (2013) 206e219

production of electricity [35]. Fig. 14 shows the general trends of the electricity production (in GWh) of both thermal and hydraulic sources for the selected countries during the period 1980e2010. The data in the figure was obtained from [11]. As can be seen this figure, thermal is the main electricity generation source in the developing countries selected for this study except Brazil while hydro is the first largest electricity generation source in the developed countries selected for this study. On the other hand, Brazil, Canada, and Norway are excessively dependent on hydropower in meeting the electricity needs. However, these countries have some difficulties in the years of drought because of these dependencies. Therefore, they are trying to diversify power generation resources. In this context, it is gaining great importance to create the diversity of energy resources and to assess the indigenous and renewable energy resources. Annual variations of hydroelectricity in the total electricity generation for the focused countries are illustrated in Fig. 15 in which the data was obtained from [11]. Hydro dependencies of Brazil, Canada, and Norway can be clearly seen from this figure. Hydro contribution in the total electricity generation for Norway

160 140 120

has remained constant around 99% during almost 30 years. It decreased about 9% in Brazil and Canada. The share of hydro in China’s total electric production dropped from 20% in 1980 to 18% in 2010 with 2% decrease. Hydro contribution in total electricity generation decreased about 22% and 27% in Turkey and India, respectively. 5.4. The contribution of hydropower to the total renewable electricity generation Renewable sources provided 55.1 TWh of electricity in 2010, or 27.4% of the total power generation in Turkey. Hydropower accounted for 93% (51.3 TWh) of this total and wind power and geothermal energy for 6.2% (3.4 TWh). The remaining 0.7% came from renewables and wastes (0.4 TWh). Hydropower generation varies according to rainfall and since 2000 has ranged from the low of 24 TWh in 2001 to the high of 51 TWh in 2010. Fig. 16 presents hydroelectricity contribution in the total renewable electric generation for the selected countries. The data in the figure was obtained from [11]. As can be seen from this figure, while

450

TURKEY

hydro thermal renewables

Electricity generation (TWh)

Electricity generation (TWh)

180

100 80 60 40 20 0 1980

217

350 300 250 200 150 100 50 0

1990

2000

2010

1980

1990

2000

600 500

INDIA

hydro thermal renewables nuclear

400 300 200 100

Electricity generation (TWh)

Electricity generation (TWh)

700

3500

CHINA

hydro 3000

thermal

2500

renewables

2000

nuclear

1500 1000 500 0

0 1980

1990

2000

1980

2010

1990

Years

120 100 80 60 40 20 0 1980

700

NORWAY

hydro thermal renewables

Electricity generation (TWh)

Electricity generation (TWh)

140

2000

2010

Years

180 160

2010

Years

Years 800

BRAZIL

hydro thermal renewables nuclear

400

CANADA

hydro 600

thermal

500

renewables

400

nuclear

300 200 100 0

1990

2000 Years

2010

1980

1990

2000 Years

Fig. 14. The general trends of total electricity generation by energy sources in the selected countries.

2010

218

A. Akpınar / Renewable Energy 51 (2013) 206e219

Fig. 15. Hydroelectricity contribution in the total electricity generation.

Fig. 16. Hydroelectricity contribution in the total renewable electricity generation.

hydropower is dominant in renewable electric generation during whole years in Canada and Norway, it is observed in the developing countries that hydro contribution slightly decreased because of increase in the production of other renewable energy sources in recent years.

would not need to meet its energy demand through import. In addition, Turkey has very large potential of hydraulic energy but to date only one-third of this significant economic potential could be used. This ratio seems insufficient when compared with that of European countries [36]. The International Energy Agency (IEA) has foreseen 53% increase of the current use of world hydroelectric power and other renewable energy sources by 2020, which is a sign that all hydroelectric potential will be put into operation. The European Commission incorporated an action plan into the European Union strategies to double the ratio of renewable energy sources in the gross internal energy consumption (from 6% to 12%) and to increase the same ratio to 22.1% in terms of electric generation by 2010 [24].

5.5. The status of usage of hydropower potential Turkey is a rapidly growing country regarding its economy and population and therefore has a large and continuously increasing energy demand. Turkey mostly meets its energy demand from imported fossil sources. However apart from petroleum and natural gas, Turkey has almost all kinds of energy resources and hence it

Table 6 Hydroelectric potential and its usage status in some countries. Country

Gross theoretical potential (TWh/yr)a

Technically feasible potential (TWh/yr)a

Economically feasible potential (TWh/yr)a

Developed in 2010 (TWh/yr)b

Usage rate of economically feasible potential (%)

Norway Canada China Brazil India Turkey

560 2216 6083 3040 2638 433

200 981 2474 1488 660 216

187 536 1753 811 600 140

116 347 713 401 110 51

62.0 64.7 40.7 49.5 18.3 36.4

a b

The data was obtained from [36]. The data was obtained from [11].

A. Akpınar / Renewable Energy 51 (2013) 206e219

Canada has developed 64.7% of the country’s economically feasible hydroelectric potential while Norway realized 62%, Brazil 49.5%, China 40.7%, India 18.3%, and Turkey 36.4% (Table 6). As can be seen from this table, the developed countries focused in this study have evaluated a significant part of their hydro potential. However, there is underdeveloped hydro potential in the developing countries, especially India and Turkey. To meet the electric energy needs, this undeveloped potential should be evaluated by Turkey and other developing countries. 6. Conclusions The main conclusions that can be drawn from the present study are listed below: U Turkey is 16th largest hydroelectric producer amongst the world countries with 35.96 TWh/yr in 2009. U Hydropower is currently the largest renewable source of electricity globally. It is an important energy source for generating electricity globally due to its useful characteristics such as being renewable, clean, less effective to the environment, inexpensive, and a national energy source. U The contribution of hydropower in the total electricity generation in Turkey is greater than that of China and India, but it is lower than that of Norway, Brazil, and Canada. U Hydropower is dominant in renewable electric generation during whole years in Canada and Norway. On the other hand, because of increase in the production of other renewable energy sources in recent years, hydro contribution slightly decreased in the developing countries that formed the focus of this study. U The developed countries focused in this study have evaluated a significant part of their hydro potential. However, there is underdeveloped hydro potential in the developing countries, especially India and Turkey. U Hydropower is the second largest contributor in meeting Turkey’s electric energy needs after thermal, mainly natural gas. A vast amount of economically feasible hydro potential (about 64%) in Turkey is undeveloped. Therefore, the contribution of hydropower will continue in the future years. U Finally, discussions between the electric sectors of the selected countries also show that it is gaining great importance to create the diversity of energy resources and to assess the indigenous and renewable energy resources. References [1] Nautiyal H, Singal SK, Sharma A. Small hydropower for sustainable energy development in India. Renewable and Sustainable Energy Reviews 2011;15:2021e7. [2] Bakıs R. The current status and future opportunities of hydroelectricity. Energy Sources, Part B: Economics, Planning, and Policy 2007;2:259e66. [3] Altinbilek HD. Hydropower development in Turkey. International Journal on Hydropower and Dams 2002;9:61e5. [4] Bakıs¸ R. Electricity generation from existing multipurpose dams in Turkey. Energy Exploration and Exploitation 2005;23:495e516. [5] Berkun M. Environmental evaluation of Turkey’s transboundary rivers’ hydropower systems. Canadian Journal of Civil Engineering 2010;37:648e58. [6] Dursun B, Gokcol C. The role of hydroelectric power and contribution of small hydropower plants for sustainable development in Turkey. Renewable Energy 2011;36:1227e35. _ Restructuring of Turkey’s electricity market [7] Uzlu E, Akpınar A, Kömürcü MI. and the share of hydropower energy: the case of the Eastern Black Sea basin. Renewable Energy 2011;36:676e88. _ Özölçer IH, _ S¸enol A. Total electricity and hydroelectric [8] Akpınar A, Kömürcü MI, energy generation in Turkey: projection and comparison. Energy Sources, Part B: Economics, Planning, and Policy 2011;6:252e62.

219

[9] Erdogdu E. An analysis of Turkish hydropower policy. Renewable and Sustainable Energy Reviews 2011;15:689e96. [10] Key World Energy Statistics, International Energy Agency (IEA), Paris, France, http://www.iea.org/textbase/nppdf/free/2011/key_world_energy_stats.pdf [accessed 05.02.2012]. [11] International Energy Statistics, US Energy International Administration (EIA), http://www.eia.gov/cfapps/ipdbproject/IEDIndex3.cfm? tid¼2&pid¼2&aid¼12 [accessed 05.02.2012]. [12] Energy policies of IEA countries: Turkey 2009 review, International Energy Agency (IEA), Paris, France, http://www.iea.org/textbase/nppdf/free/2009/ turkey2009.pdf [accessed 05.07.2012]. [13] Seifert J. Brazilian energy policy: new dynamics between regional integration and self-sufficience, Joint Conference Whatever Happened to North-South?, February 16e19, Sao Paulo, Brazil, http://www.saopaulo2011.ipsa.org/sites/ default/files/papers/paper-1207.pdf [accessed 05.02.2012]. [14] Volpi G, Jannuzzi G, Gomes RDM. A sustainable electricity blueprint for Brazil. Energy for Sustainable Development 2006;X:14e24. [15] Energy policies of IEA countries: Canada 2009 review, International Energy Agency (IEA), Paris, France, http://www.iea.org/textbase/nppdf/free/2009/ canada2009.pdf [accessed 05.07.2012]. [16] Energy policies of IEA countries: Norway 2011 review, International Energy Agency (IEA), Paris, France, http://www.scribd.com/doc/54656814/EnergyPolicies-of-IEA-Countries-Norway-2011-9264098151 [accessed 05.07.2012]. [17] Remme U, Trudeau N, Graczyk D, Taylor P. Technology development prospects for the Indian power sector. International Energy Agency (IEA). Information paper, Paris, France, http://www.iea.org/papers/2011/technology_development_india. pdf; 2011 [accessed 05.07.2012]. [18] China Electricity Market. Investment in China’s demanding and deregulating power market. China Electricity Council, http://www.hu.capgemini.com/m/ hu/tl/China_Electricity_Market_2006.pdf; 2006 [accessed 05.10.2012]. [19] Carbon emission policies in key economies, Appendex E: China’s electricity generation sector, Productivity Commission Research Report (PCRR), Australian Government Productivity Commission, Canberra, Australia, http://www. pc.gov.au/__data/assets/pdf_file/0005/109922/14-carbon-prices-appendixe. pdf [accessed 05.10.2012] [20] Kaygusuz K. Electricity generation: a case study in Turkey. Energy Sources 1999;21:275e90. [21] Ozturk M, Bezir NC, Ozek N. Hydropowerewater and renewable energy in Turkey: sources and policy. Renewable and Sustainable Energy Reviews 2009; 13:605e15. [22] Kaygusuz K. Hydropower and the world’s energy future. Energy Sources 2004; 26:215e24. _ Kankal M. Development of hydropower energy in [23] Akpınar A, Kömürcü MI, Turkey: the case of Çoruh river basin. Renewable and Sustainable Energy Reviews 2011;15:1201e9. _ The 5th World Water Forum, Istanbul, Turkey, http://www2. [24] Water and DSI, dsi.gov.tr/english/pdf_files/dsi_in_brief2009.pdf, [accessed 05.02.2012] [25] Turkey country report, The 3rd World Water Forum, Kyoto, Japan, http:// www.worldwatercouncil.org/fileadmin/wwc/Library/Publications_and_ reports/country_reports/report_Turkey.pdf [accessed 05.02.2012] _ Akpınar A. Hydropower energy versus other energy sources in [26] Kömürcü MI, Turkey. Energy Sources, Part B: Economics, Planning, and Policy 2010;5: 185e98. _ Kankal M, Özölçer IH, _ Kaygusuz K. Energy situation [27] Akpınar A, Kömürcü MI, and renewables in Turkey and environmental effects of energy use. Renewable and Sustainable Energy Reviews 2008;12:2013e39. [28] Kaygusuz K. Sustainable development of hydroelectric power. Energy Sources 2002;24:803e15. [29] Yumurtacı Z, Asmaz E. Electric energy demand of Turkey for the year 2050. Energy Sources 2004;26:1157e64. [30] Cambodia National Mekong Committee National Sector Review 2003: hydropower by ministry of industry, mines and energy, http://www. mekonginfo.org/assets/midocs/0001935-society-national-sector-review.pdf [accessed 05.02.2012]. [31] Paish O. Small hydropower: technology and current status. Renewable and Sustainable Energy Reviews 2002;6:537e56. _ The list of hydropower plants [32] General Directorate of Stage Hydraulic Works (DSI), projects, http://www2.dsi.gov.tr/skatablo/Tablo1.htm [accessed 05.07.2012]. [33] Ozturk HK, Yilanci A, Atalay O. Past, present and future status of electricity in Turkey and the share of energy sources. Renewable and Sustainable Energy Reviews 2007;11:183e209. [34] World Bank. Economic and energy indicators, http://data.worldbank.org/ indicator; 2010 [accessed 05.02.2012]. [35] Ceylan H, Ozturk HK. Modeling hydraulic and thermal electricity production based on genetic algorithm-time series (GATS). International Journal of Green Energy 2004;1:393e406. [36] Araujo JL, Rosa LP, Silva NF. Hydroelectricity: future potential and barriers. In: Sioshansi F, editor. Generating electricity in a carbon-constrained world. London, UK: Academic Press of Elsevier; 2010. p. 323e46.